The "brains" of the system run on useless software that will not work without a hardware dongle. Check before you buy, I'm sure there are plenty of vendors who pull the same shit out there
Also, are you SURE that a keypress box (lockable box with hooks for hanging keys) won't do? When I was in the military, that's what we did. Never had a problem as:
a) We exchanged keys for identification (no ID, no key!)
b) If you lose the key or run away, we have your id, and we will hunt you down.
With a well-kept logbook, you cannot go wrong. Not to mention, no dicking about auditing whose keycard has access to which area when. If the key is missing from the keypress box, someone is using it. If it's missing after the official visitor hours, you have a problem. Scales pretty well up to a few hundred keys.
Of course, make sure you buy decent locks. Also, someone could always try to forge the keys. But that's what armed escorts are for.